Trigger actuated switch device



L E Z N E R F m C TRIGGER ACTUATED SWITCH DEVICE 2 Sheets-Sheet 1 FiledDec. 27. 1965 CARL J. FRENZEL JM/fi ATT'YS United States Patent Cilice3,309,484 Patented Mar. 14, 1967 3,309,484 TRIGGER ACTUATED SWITCHDEVICE Carl J. Frenzel, Chicago, llL, assignor to Skil Corporation,Chicago, Ill., a corporation of Delaware Filed Dec. 27, 1965, Ser. No.516,331 Claims. (Cl. 200157) claims a variable speed control system forportable power tools, such as power drills, which system includes asilicon controlled rectifier circuit having a variable resistor orpotentiometer operated by the tool trigger. In this system, the speed ofthe tool motor is increased as the tool trigger is depressed orsqueezed. By way of example, the speed of the tool motor may begradually varied from 0 to 2,000 r.p. m.

In performing some operations using a power tool provided with a speedcontrol system, such as the aforementioned Gawron system, it may bedesirable to operate the tool a number of times, in a consecutivemanner, at a predetermined speed, say 1,000 rpm. and/or it may bedesirable to operate the tool for an extended period of time at apredetermined constant speed. The present invention provides a triggeractuated switch device for use with a tool and speed c-ontrol system ofthe type described, which switch device includes an adjustable stop {forvarying the stroke of the trigger to allow operation of the associatedtool at a desired or predetermined speed by squeezing the trigger untilit is stopped, and which switch device further includes locking meansfor locking the trigger at any and all of its stopped positions.

A primary object of the present invention is the provision of a triggeractuated switch device including unique, manually operable means foradjusting the stroke of the trigger.

Another object of the present invention is the provision of a triggeractuated switch device having adjustable stop means for varying thestroke of the trigger and further including locking means for releasablylocking the trigger in any andall of its stopped positions.

Still another object of the present invention is the provision of atrigger actuated switch device capable of fulfilling the aforementionedobjects and also being capable of providing precision-like control ofthe tool trigger thereby to provide "corresponding control of the speedof the associated motor.

These and other objects and advantages of the invention will becomeapparent from the following specification disclosing a preferredembodiment of the invention which is illustrated in the accompanyingdrawings where- FIG. 1 is a partially sectioned side elevation of oneembodiment of the trigger actuated switch device of the presentinvention showing the same mounted in a portable tool, such as a powerdrill;

FIG. 2 is a partially sectioned top plan View of the switch showing thetrigger in its fully extended or off position;

FIG. 3 is a partially sectioned top plan view of the switch deviceshowing the trigger in one of its stopped positions;

FIG. 4 is a partially sectioned side elevation of the switch device inthe configuration illustrated in FIG. 3; and

FIG. 5 is an exploded, perspective view of the trigger operated switchdevice.

Referring now to the drawings, the illustrated embodiment of the triggeractuated switch device of this invention includes a trigger 10 ofunitary construction having a finger engageable portion 10a and a stemportion 10b. The switch unit further includes a casing 11 having a sheetmetal member 12 defining a guideway slidably receiving stem portion 10bof the trigger. Stem portion 10b includes or carries an upwardlyextending projection or button 14 which is received in an elongated slot15 formed in the top wall of casing 12 Abutting engagement of the button14 with opposite ends of the slot 15 determines the maximum stroke ofthe trigger. A spring 16 contained within the casing 12 yieldably urgesthe trigger 10 to its outermost or extended position, i.e., the offposition, which is established by abutting engagement of button 14 withthe front end of slot 15 (see FIG. 1). One end of spring 16 abuts an endplate 18 of the casing 12, and the other end of the spring is receivedwithin a cavity 19 formed in trigger stem 10b.

Casing 11 includes suitable means 20 defining a compartment adapted toreceive the various components of a control system, such as the variablespeed control system disclosed and claimed in the aforementioned Gawronpatent. As mentioned above, the Gawron system includes a variaberesistor which is operated by trigger movement. By way of example, thisvariable resistor may consist of a contact carried by trigger stem 10band slidable along a rectilinear contact strip of resistance material(not shown) supported by member 20 so that the resistance is changed bymovement :of the trigger. As explained in the aforementioned Gawronpatent, this change of resistance causes a corresponding change in thespeed of the tool motor. Preferably, stem 10b and member 20 will alsoinclude cooperating contacts and contact strips constituting the on-offand by-pass switches referred to in the above mentioned Gawron patent.

The finger engageable portion 10a of the trigger includes a recess 22,and the stem portion 10b of the trigger includes a recess 23. Recesses22 and 23 are in communication with each other. A lug or nut 24 isreceived within recesses 22, 23. Recess 22 has opposite side walls, andrecess 23 has one side wall, all of which side walls act to preventrotation of lug 23 as will become apparent from the followingspecification. Lug 24 includes a threaded through bore 25. A catch plate26, either integral with plate 24 or suitably secured thereto, includesan opening 27.

Finger engageable portion 10a of the trigger has a cavity or cut-out 29at the front thereof. Portion 10a of the trigger also has a bore 30 withthe central axis thereof extending parallel with the direction oftrigger movemeint. Bore 30 opens at one end of its ends into recess 22and opens at its other end into the cavity or cut-out 29.

An adjustment screw 32 has a cylindrical portion 33 rotatably receivedin bore 30 of trigger portion 10a. This cylindrical portion includes anannular groove 33a. Trigger portion 10a includes a cross bore 34 inwhich a pin 35 is received. As noted in FIG. 1, the pin 35 extends intoannular groove 33a of the adjustment screw. It will be apparent that theadjustment screw 32 may be rotated relative to the trigger but tha axialmovement beween the adjustment screw and the trigger is prevented by thepin'35. The adjustment screw further includes a knurled knob or buttonportion 37 which is received within the cut-out or cavity 29 of thetrigger 10.

The adjustment screw 32 has a threaded shank por- 1) tion 38 threadinglyreceived in the threaded opening 25 of the lug 24. This threaded portionof the shank actually serves to support the lug on the trigger. Asmentioned above, the various side walls of recesses 22 and 23 preventrotation of the lub 24. Therefore, it will be apparent that uponrotation of the adjustment screw 32, lug 24 will be moved along theshank 38 i.e., relative to the trigger, depending on the direction ofrotation of the adjustment screw 32. Movement of lug 24 causes movementof plate 26 as these two members are either integral or suitably securedtogether.

Lug 24 includes a lip or abutment face 240, which face is arranged forabutting engagement with edge 12a of the casing (see FIGS. 4 and 5).Abutting engagement of face 24a and 12a stops the trigger, i.e., limitsthe amount of movement or the stroke thereof.

One side wall of the casing 12 includes a bent-out portion 12b (FIGS. 2and 3) having an opening 39 therein. A sleeve 40 includes areduced-in-diameter portion 40a at one end thereof, which portion isfitted within the opening 39. This engagement between opening 39 andreduced-in-diameter portion 40a serves as a means for mounting thesleeve 40 on the casing 12. Sleeve 40 includes a first bore 40b and acoaxial, largerin-diameter bore 40c. A pin 42 having a head 42a isslidably mounted in bore 4017. A button 43 is secured to the outer endof pin 42, which button is slidably received within bore 40c. A spring44 encircles pin 42. One end of the spring abuts an annular shoulderbetween bores 40b, 40c, and the other end of the spring abuts the innerend of button 43.

The spring 44 acts to urge pin 42 and button 43 outwardly with the head42a of the pin against reduced-indiameter end 40a of the sleeve (seeFIG. 3). As will be explained hereinbelow,.pin 42 is adapted to beinsertcd in opening 27 of the plate 26 for locking the trigger in itsfully depressed or stopped position which is determined by abuttingengagement of button 14 with the inner end of slot 15 and in any stoppedposition determined by abutting engagement of face 24a with casing edge120.

For purposes of the following discussion of the operation of the triggeractuated switch device of this invention, assume that the same ismounted within the pistol grip portion of a portable tool, such as apower drill. The pistol grip portion of a power tool is fragmentarilyillustrated in FIG. 1 and designated by the numeral 45. When the triggeroperated switch unit is mounted in the handle grip portion of the tool,trigger portion a extends outwardly through an opening 46 in the toolhousing thereby to permit manual depression of the trigger. The toolhousing also includes an opening (not shown) for accommodating sleeve 40of the locking mechanism. Assume further, for purposes of illustrationonly, that the compartment 20 contains the various components of thevariable speed control system covered in the aforesaid Gawron patent.The trigger 10 will be connected to the variable resistor in suchcircuit so that as the trigger is depressed, the speed of the associatedtool motor is correspondingly increased.

If it is not desired to use the adjustable stop and locking feature ofthe present invention, knurled knob 37 of the adjustment screw 32 isrotated for moving lug 24 to the left until it is fully seated withinthe recess 22 (FIGS. 1 and 2). In this position of the lug 24, thetrigger may be squeezed or depressed until the button 14 comes intoabutting engagement with the inner end of slot 15. With the trigger inthis position, i.e., its maximum position, maximum speed of theassociated tool is obtained. When trigger 10 is depressed as justexplained, face 24a may be in abutting engagement with edge 12a or theremay be a slight space between these two surfaces.

If it is desired to operate the tool motor at a speed somewhat less thanits maximum speed, knob 37 of the adjustment screw is rotated forrunning lug 24 to the right as illustrated in the drawings. Experiencein using a tool incorporating the present invention will enable theoperator to know approximately how many revolutions of the knob 37 arerequired to bring about the desired speed of the tool. Of course,indicia (not shown) on either the button 37 or the trigger or both couldbe provided to indicate various speeds or trigger positions. After thelug 24 has been run along the threaded portion 38 of the adjustmentscrew by rotating the same, the trigger is squeezed until face 2441comes into abutting engagement with edge 12a. If the speed of the motoris not as desired, the trigger can be released and the knob 37 rotatedin one direction or the other in order to change the speed of the motorwhen the trigger is again depressed.

When face 24a is brought into abutting engagement with edge 12a of thecasing by squeezing of the trigger, opening 27 in plate 26 is inalignment with pin 42. Accordingly, if it is desired to lock the triggerin its stopped position, i.e., its position wherein face 24a is inabutting engagement with edge 12a, button 43 is depressed therebycausing head 42a of the pin to be forced through the opening 27 in theplate 26. Releasing of the trigger will allow the spring 16 to force thetrigger slightly forwardly until the trailing portion of the opening 27engages the shank of the pin 42 adjacent the head 42a. The trigger isunlocked by squeezing the trigger slightly until the opening 27 isbrought into alignment with head 42a; when the trigger is in thisposition, spring 44 will act to force pin 42 outwardly clear of theplate 26, thereby releasingthe trigger. It should also be mentioned thatwhen lug 24 is in its forwardmost position relative to the trigger andwhen the trigger is depressed its maximum amount determined by button 14abutting the innermost end of the slot 15, the opening 27 is inalignment with pin 42 thereby permitting the trigger to be locked in itsmaximum depressed position. Locking the trigger in this position permitscontinuous operation of the tool at its maxium speed.

-It should be noted that if the trigger is depressed and locked againstmovement by pin 42, rotation of the adjustment button 37 will then causemovement of the trigger and, accordingly, a change in the speed of theassociated tool motor. This result occurs because the engagement of thepin 42 in the opening 27 prevents axial movement of the lug '24.Therefore, when the adjustment screw 32 is rotated, the latter and thetrigger itself are moved. When the trigger is locked by the pin 42 andthe button 3-7 rotated as just described, the button 37 acts as avernier to provide precise trigger control and therefore correspondingspeed control for the associated motor.

It should be apparent that the present invention provides a unique meansfor adjusting or varying the stroke of the tool trigger and for lockingthe tool trigger when it is squeezed and stopped by operation of theadjustable stop. The knob 37 can be readily manipulated; this knob doesnot require an additional opening in the power tool housing as theformer is contained within the tool trigger. As explained above, whenthe locking mechanism is actuated first and the adjustment screw thenrotated, the latter acts as a vernier for providing precision-likecontrol of the speed of the associated tool motor.

While the invention has been shown in but one form, it will be obviousto those skilled in the art that it is not to be so limited. On thecontrary, the invention is susceptible of various forms andmodifications without departing from the spirit and scope of theappended claims.

I claim:

1. In a portable tool having a trigger receiving housing aperture,wherein the tool is of the type adapted to contain a control systemcapable of varying the speed of the tool motor in response to the amountof trigger movement, a trigger actuated switch device for mounting insaid tool with the trigger extending through said aperture for manualdepression, said switch device comprising, a casing, a trigger mountedby the casing foroscilla ting movement, resilient means carried by thecasing and engaged with the trigger for urging the same to its extendedpositiofnsaid trigger including guide means extending in parallelrelation with the direction of trigger movement, lug means carried bysaid trigger' and engaged with said guide means for movement in eitherdirection therealong, a manually operable adjustment means including amember ro'tatably carried by the triggerand engaged with said l'ug meansfor moving the same in either direction along said path of movementthereof, and abutment means on said casing arranged to be engaged bysaid lug means upon depression of the trigger thereby to limit theamount of movement of the latter for establishing a selected speed ofthe tool motor.

2. In a portable tool having a trigger receiving housing aperture,wherein the tool is of the type having a control system capable ofvarying the speed of the tool motor in response to the amount of triggermovement, a trigger actuated electric switch device for mounting in saidtool with the trigger extending through said aperture for manualdepression, said switch device comprising, a casing and a triggermounted thereby for oscillating movement, said device also includingresilient means interposed between said casing and said trigger forurging the latter to its extended position, abutment means carried bysaid casing, adjustment means carried by said trigger including anelement movable relative to the latter to and away from said abutmentmeans along a path corresponding to' the path of movement of thetrigger, said element being arranged toabut said abutment means upondepression of the trigger thereby to limit the amount of movement of thelatter for establishing a selected speed of the tool motor, said deviceincluding locking means engageable with said element for locking saidtrigger in any one of its positions determined by engagement of saidelement with said abutment means.

3. The switch device according to claim 1 wherein said adjustment meansincludes a button rotatably mounted in a bore in said trigger and beingexposed for manual control.

4. The switch device according to claim 3' wherein said adjustment meansfurther includes a screw connected to said button for rotation thereby,and wherein said lug means includes a member having an openingthreadingly receiving said screw.

5. The switch device according to claim 1 further defined by, triggerlocking means including a locking pin, which locking means is mounted onsaid casing for extending through a bore in the tool housing thereby toexpose said pin for manual depression, catch means carried by said lugmeans and adapted to be releasably locked .by said pin when the catchmeans is aligned with the pin.

6. A trigger actuated switch device for mounting in the housing of aportable toolwith the trigger extending through a housing aperture formanual depression, wherein the tool is of the typeadapted to contain acontrol system capable of varying the speed of the tool motor inresponse to the amount of trigger movement, said switch devicecomprising, a casing, a trigger mounted by the casing for reciprocatingmovement relative thereto, resilient means carried by the casing andengaged with the trigger for urging the same to its extended position,said trigger including means defining a guideway extending parallel withthe direction of trigger movement, a lug in said guideway and adaptedfor movement in either direc- 6 tion therealong, which lug includes athreaded opening extending parallel with the direction of movement ofthe lug, said trigger including a bore extending parallel with thedirection of trigger movement and opening at the front of said trigger,adjustment screw means rotatably mounted in said bore and having aportion thereof disposed exteriorly of said trigger adjacent the frontthereof, means for preventing axial movement of said adjustment screwmeans relative to said trigger, said adjustment screw means beingthreadingly engaged in the opening of said lug for moving the latter inresponse to rotation of the former, and abutment means on said casingarranged to be engaged by said lug upon depression of the triggerthereby to limit the amount of movement of the latter.

7. The switch device according to claim 6 further defined by, triggerlocking means including a locking pin, which locking means is mounted onsaid casing for extending through a bore in the tool housing thereby toexpose said pin for manual depression, catch means carried by said lugand adapted to be releasably locked by said pin when the catch means isaligned with the pin.

8. A trigger actuated switch device for mounting in the housing of aportable tool with the trigger extending through a housing aperture formanual depression, wherein the tool is of the type adapted to contain acontrol system capable of varying the speed of the tool motor inresponse to the amount of trigger movement, said switch devicecomprising, a casing, a trigger mounted by the casing for reciprocalmovement relative thereto, resilient means carried by the casing andengaged with the trigger for urging the same to its extended position,said trigger including means defining a guideway extending parallel withthe direction of trigger movement, a lug in said guideway and adaptedfor movement in either direction therealong, which lug includes athreaded opening extending parallel with the direction of movement ofthe lug, said trigger including a cavity at the front thereof, saidtrigger further including a bore extending parallel with the directionof trigger movement and opening into said cavity, an adjustment screwrotatably mounted in said bore and having the head thereof receivedwithin said cavity, means for preventing axial movement of saidadjustment screw relative to the trigger, said adjustment screw having athreaded portion threadingly engaged in the opening of said lug formoving the latter in response to rotation of the former, abutment meanson said casing arranged to be engaged by said lug upon depression of thetrigger thereby to limit the amount of movement of the latter, triggerlocking means including a locking pin, which locking means is mounted onsaid casing for extending through a bore in the tool housing thereby toexpose said pin for manual depression, catch means carried by said lugand adapted to be releasably locked by said pin when the catch means isaligned with the pin.

9. The switch device according to claim 8 wherein said catch meansincludes a plate having an opening therein for receiving said pin.

10. The switch device according to claim 8 further defined by, saidcasing including a compartment adapted to receive the components of asolid state speed control circuit.

References Cited by the Examiner UNITED STATES PATENTS 5/1929 Farley200-157

1. IN A PORTABLE TOOL HVING A TRIGGER RECEIVING HOUSING APERTURE,WHEREIN THE TOOL IS OF THE TYPE ADAPTED TO CONTAIN A CONTROL SYSTEMCAPABLE OF VARYING THE SPEED OF THE TOOL MOTOR IN RESPONSE TO THE AMOUNTOF TRIGGER MOVEMENT, A TRIGGER ACTUATED SWITCH DEVICE FOR MOUNTING INSAID TOOL WITH THE TRIGGER EXTENDING THROUGH SAID APERTURE FOR MANUALDEPRESSION, SAID SWITCH DEVICE COMPRISING, A CASING, A TRIGGER MOUNTEDBY THE CASING FOR OSCILLATING MOVEMENT, RESILIENT MEANS CARRIED BY THECASING AND ENGAGED WITH THE TRIGGER FOR URGING THE SAME TO ITS EXTENDEDPOSITION, SAID TRIGGER FOR URGING THE SAME TO ITS EXTENDING IN PARALLELRELATION WITH THE DIRECTION OF TRIGGER MOVEMENT, LUG MEANS CARRIED BYSAID TRIGGER AND ENGAGED WITH SAID GUIDE MEANS FOR MOVEMENT IN EITHERDIRECTION THEREALONG, A MANUALLY OPERABLE ADJUSTMENT MEANS INCLUDING AMEMBER ROTATABLY CARRIED BY THE TRIGGER AND ENGAGED WITH SAID LUG MEANSFOR MOVING THE SAME IN EITHER DIRECTION ALONG SAID PATH OF MOVEMENTTHEREOF, AND ABUTMENT MEANS ON SAID CASING ARRANGED TO BE ENGAGED BYSAID LUG MEANS UPON DEPRESSION OF THE TRIGGER THEREBY TO LIMIT THEAMOUNT OF MOVEMENT OF THE LATTER FOR ESTABLISHING AZ SELECTED SPEED OFTHE TOOL MOTOR.